Are you positive it is the head gasket, the heads on these cars tend to be able to take a serious amount of heat before warping, or having issues, the upper and lower intake manifolds are another story.
If you tackle those jobs, let me know and I'll post up some helpful links for you.

William, see a lot of head gaskets go on these engines(3.1/3.4'*).......way more lower intake gaskets than head gaskets......but many times have seen just the lowers replaced, and then you end up doing the job all over again to replace a head gasket...

More often than not, the head gaskets go because people know they have a coolant leak, and just continually add coolant rather than fix the problem.....this leads to air pockets and overheating, which will eventually cause a head gasket problem.......it'* been my experience, more often than not, to be #1 cylinder....

William, see a lot of head gaskets go on these engines(3.1/3.4'*).......way more lower intake gaskets than head gaskets......but many times have seen just the lowers replaced, and then you end up doing the job all over again to replace a head gasket...

More often than not, the head gaskets go because people know they have a coolant leak, and just continually add coolant rather than fix the problem.....this leads to air pockets and overheating, which will eventually cause a head gasket problem.......it'* been my experience, more often than not, to be #1 cylinder....